中国塑料 ›› 2015, Vol. 29 ›› Issue (04): 24-29 .DOI: 10.19491/j.issn.1001-9278.2015.04.005

• 材料与性能 • 上一篇    下一篇

聚乳酸扩链改性及其挤出发泡的研究

李珊珊1,何继敏1,颜克福1,金晓明2,龙洪生3   

  1. 1. 北京化工大学塑料机械及塑料工程研究所2. 北京联合大学3. 北京化工大学
  • 收稿日期:2014-08-18 修回日期:2014-12-10 出版日期:2015-04-26 发布日期:2015-04-26

Influence of Chain Extentions on Cell Structures of Extrusion Foaming of Poly(lactic acid)

  • Received:2014-08-18 Revised:2014-12-10 Online:2015-04-26 Published:2015-04-26

摘要: 采用扩链剂对聚乳酸(PLA)进行扩链改性,研究了扩链剂对PLA流变性能的影响。采用3种不同类型的化学发泡剂:发泡剂A(发泡母粒)、发泡剂B\[自制复合发泡剂:偶氮二甲酰胺(AC发泡剂)/碳酸氢钠(NaHCO3)\]、发泡剂C(自制改性AC发泡剂),利用单螺杆挤出机对PLA进行挤出发泡。采用扫描电子显微镜观察分析了发泡材料的断面泡孔结构。结果表明,加入扩链剂可有效提高PLA的熔体强度和黏度及降低其熔体流动速率,改善PLA的发泡效果,扩链剂含量为0.8份(质量分数,下同)时,发泡材料的发泡效果最好;实验所用的3种发泡剂中,发泡剂C的发泡效果最好,发泡剂含量为1.5份时,发泡样品的表观密度较小(0.6 g/cm3),泡孔直径最小(约为57 μm),泡孔密度最大(约为7.69×10^6个/cm3),泡孔分布均匀,无明显泡孔破裂和连通现象。

关键词: 聚乳酸, 扩链, 化学发泡, 挤出, 泡孔结构

Abstract: The neat PLA was modified by chain extension and the influence of the chain extender on the rheological properties was investigated. Three chemical agents, foaming agent A (Masterbatch), foaming agent B(AC+NaHCO3)and foaming agent C (modified AC), were used to investigate the foamablibity of PLA. The density and cell morphology of extrusion foamed PLA were studied. It showed that the foamability of PLA was improved by adding the chain extender, which increased viscosity and decreased the melt flow rate. The foamability was best when the chain extender content was 0.8. The size, shape, density and distribution of the cells of the foamed PLAs were examined. The best foamed PLA was found with foaming agent C, with the density, cell diameter, and cell density being 0.6 g·cm-3, 57 μm, and 7.37×10^6 per·cm-3,respectively.

Key words: poly(lactic acid), chain extension, chemical foaming, extrusion, cell structure